- 12" (model also has a plumb vial and the 18" size has a double plumb vial.
- Vials are adjustable to a positive setting and are housed in a satin finished brass tube with a friction-fit closing cover to prevent breakage.
- Base of the levels features an involute groove running the length of the base,which provides a reliable seat for round work
- The 6" through 18" main level vials have graduations that are approximately 80-90 seconds or .005" per foot
- There are five, six, or seven lines on each side of the bubble, depending on the base length.